c# - String.Replace 未按预期工作

Question

我有一个程序

    public void TestMethod2()
    {
        string[] keywords =
        {
            "SELECT", "FROM", "WHERE", "GROUP", "HAVING", "ORDER", "LEFT",  "RIGHT", "JOIN", "INNER", "OUTER", "ASC",
            "DESC", "AND", "OR","IN", "BETWEEN", "BY", "NOT", "ON", "AS", "CASE", "WHEN", "ELSE", "UPDATE", "SET"
        };

        var actualString = "SELECT * FROm A Join B On C in D case e join t left outer join inner join right join";

        foreach (var text in actualString.Split(' '))
        {
            var isExists = keywords.Any(x => x.Equals(text, StringComparison.OrdinalIgnoreCase));

            if (!isExists)
            {
                continue;
            }

            actualString = actualString.Replace(text, text.ToUpper());
        }


        var expectedString = "SELECT * FROM A JOIN B ON C IN D CASE e JOIN t LEFT OUTER JOIN INNER JOIN RIGHT JOIN";

    }

我是 C# 的新手。我不清楚为什么 Replace() 方法没有按预期工作。它正在显示输出SELECT * FROM A JOIN B ON C IN D CASE e joIN t LEFT OUTER joIN INner joIN RIGHT joIN

有人能告诉我为什么 Replace() 会这样吗？提前致谢。

Answer 1

如果调试它，您会注意到您的关键字“in”替换了第二个连接，因此您获得了连接。稍后您的文本变量将尝试用“JOIN”替换“join”，但它不会找到“join”，因为它的一部分是大写的。